WASHINGTON — President Donald Trump’s abrupt firing of FBI Director James Comey roiled the Senate Wednesday as Majority Leader Mitch McConnell rejected calls for a special prosecutor and Democrats ended all hearings at noon to protest the dismissal.

McConnell began a chaotic day by staunchly defending Trump, warning that a special prosecutor would hinder existing probes into Russian meddling in the presidential election last year, and questioned why Democrats objected to Comey’s dismissal when they had condemned him for his handling of the Hillary Clinton email probe.

“Today we’ll no doubt hear calls for a new investigation, which could only serve to impede the current work being done,” McConnell said at the start of the Senate session by dismissing demands for a special prosecutor as “partisan.”

Senate Minority Leader Chuck Schumer (D-N.Y.) said in his opening remarks that not only should a special prosecutor be appointed, but that the two top Justice Department officials who recommended Comey’s firing should be called to brief all senators about their advice.

“If there was ever a time when the circumstances warranted a special prosecutor, it is right now,” Schumer said in his opening remarks.

“We know Director Comey was leading an investigation into whether the Trump campaign colluded with the Russians — a serious offense,” Schumer said. “Were those investigations getting too close to home for the President?”

Most Republicans backed McConnell’s stand, but a handful of them voiced concerns, including Arizona Sens. John McCain and Jeff Flake, and Tennessee Sen. Bob Corker.

After a morning caucus meeting to discuss strategy, Democrats ratcheted up their criticism of the whole process that led to Trump’s sacking of Comey.

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Sen. Ron Wyden (D-Ore.) charged that Attorney General Jeff Sessions had shown a disregard for his recusal from involvement in any Russia investigation by joining Deputy Attorney General Rod Rosenstein in recommending that Trump fire Comey.

Rosenstein also came under criticism.

Sen. Dianne Feinstein (D-Calif.), the top Democrat on the Judiciary Committee, said Rosenstein’s memo did not include any “legal theory” or legal basis, but just quoted former Justice officials about Comey’s handling of the Clinton email investigation.

Feinstein said both Rosenstein and Sessions, who already had recused himself from any Russia investigation because of his role in Trump’s campaign, should step aside and let the highest-ranking career official name a special prosecutor.

Schumer later made that recommendation on the Senate floor.

And Democrats invoked what’s called the two-hour rule, barring any committee hearings to continue after noon.

Schumer became a target of angry tweets by Trump, who called him “Cryin’ Chuck” and accused Democrats who previously had complained about Comey “hypocrites” for their outrage at Trump’s removal of the FBI director.

Sen. John Cornyn (R-Tex.) sought to rebut Democrats’ charges that Trump might be trying to squelch the Russia probe by saying the firing didn’t make Comey go away.

The Senate Intelligence Committee, which is conducting an investigation into Russian meddling, announced FBI Deputy Director Andrew McCabe would replace Comey at its Thursday hearing on worldwide threats.

But the committee chairman, Sen. Richard Burr (R-N.C.), and vice chairman, Sen. Mark Warner (D-Va.), also announced they had invited Comey to testify next week at a closed hearing. Warner said that Comey had not responded to the invitation as of Wednesday afternoon.

Burr said the Comey dismissal could create “challenges” for the committee’s investigation, because Comey had been very cooperative. “It wouldn’t in any way shape or form preclude us from coming to a conclusion,” Burr said, “but it might delay us.”